1. Field of the Invention
The present invention relates generally to a light source driving apparatus, and more particularly, to an apparatus for driving a light source included in a projector.
2. Description of the Related Art
To drive a projector, a color filter method or a color sequential method is used. A white Light Emitting Diode (LED) is widely used as a light source employed in the color filter method and the light source is driven using Direct Current (DC). A projector of the color sequential method typically uses three-color LED light sources of red, green, and blue and sequentially drives the LED light sources using time-division pulses. For a mobile projector, the color sequential method, which is capable of improving optical efficiency, is preferred.
FIG. 1 is a circuit diagram illustrating a conventional light source driving apparatus for driving an LED light source. Referring to FIG. 1, the light source driving apparatus includes a light source power supply 10, an LED light source 20, a switching device 30, and a feedback circuit comprised of resistors R1 and R2.
The light source power supply 10 supplies a power source necessary to drive the LED light source 20. A current ILED flows into the LED light source 20 from the light source power supply 10 by an operation of the switching device 30 based on an externally input control signal EN. The LED light source 20 generates light of a brightness corresponding to the current ILED. The current ILED flowing into the LED light source 20 is branched through a feedback power resistor 40 and the branched current is supplied to a feedback terminal FB. The light source power supply 10 controls the power source necessary to drive the LED light source 20 using a voltage value provided to the feedback terminal FB.
The feedback circuit includes the feedback power resistor 40 which generally uses a high-power rated resistor. However, the resistor functions as a main cause of power loss of the light source driving apparatus and deteriorates the power efficiency of the light source driving apparatus.